GLOBAL TEMPERATURE CHANGES - MY WARMING WORLD

The 10 warmest years in the 134-year record all have occurred since 2000, with the exception of 1998. The year 2015 ranks as the warmest on record. The global temperature has increased 0'87ºC.

Source: http://climate.nasa.gov/vital-signs/global-temperature/

And, what has been happening where I live?

To understand what is happening we can use the CMIP5 Global Climate Change Viewer. It is an interactive map to look at the global annual mean temperature changes. The black line shows observations from 1980-2004, the blue line is the model control simulation and should closely follow the black line and the red line is the future projection for 2050-2074 for the country you have selected.

According with the graphics, Spain observations and 1980-2004 simulations are very closed together for temperature, with the future projections showing a general increase over all 12 months. In Spain we can expect that the temperature will rise up to 4 ºC (2050-2074).

Furthermore, in the picture we can clearly observe that the northern part will have an increased temperature rise than the southern part.

Although predictions and simulations are quite similar, the precipitation observations and 1980-2004 simulations are quiet differentt. Observations from january to april are lower than predictions and simulations and from september to november are higher. It should be stressed that precipitations tend to decrease.

According to the information above we have to considere largest threats in Spain. 

In Spain the increase of temperature and reduction of rainfall will create ideal conditions for increasing forest fires. Also the sea level is expected to rise and the land of the coasts will suffer the risk of flooding.
The increase in temperature will allow the proliferation of exotic species like zebra mussel and some native species, like oso pardo, will face with the complete disappearance of the favourable weather conditions for their survival.
The climate change also could have influence in the economy. Wine’s production will be affected by the higher risk of frost, under periods of ripening of the grapes, water shortages and changing patterns of pests and diseases. The fisheries sector is worrying about jellyfish, whose presence seriously damage fishing. Furthermore, the Mediterranean area will have a higher incidence of heat waves and droughts affecting the tourism. And finally, cereal crops will be devastated by drought. As the weather becomes less predictable, agriculture in Spain will become more difficult.

SIGNS OF CLIMATE CHANGE - EXTREME EVENTS

How has our climate changed?

In 2013 in March, Spain received more than three times its monthly average precipitation, making it the wettest March since national records began in 1947. Normal precipitation across the country is just 46 millimeters, yet the country received 157 millimeters through the month. Rising rivers threatened many areas with floods.

Source:

https://www.climate.gov/news-features/featured-images/state-climate-extreme-events

The frequency of heavy precipitation has increased over most land areas in Spain, in my opinion this extreme event is related with reaching extrem temperatures that evaporate more water from the oceans.

In the south, Africa suffered droughs however, in the north the spring was unusually cold. Weather is behaving uncommonly everywhere. I would like to emphasise that this year in Ourense, the city where I live, the temperature in winter is higher than previous years and people is concerned about it.

Here other example in 2015,

Extrem weather events seems to be more frequent every year and they are a sign of climate change.

REFLECTION WEEK 2

WEEK 2

One challenge more.

This was a really fascinating week, I'm amazed by the complexity of the topic. Personally, I have found the concept of 'snowball earth' very interesting, I have never heard of this before therefore, I required further reading which I thoroughly enjoyed doing.

All the new information of this week have been harder to comprehend however I have enjoyed looking for more information about paleoclimatology, volcanoes, isotopes and more inetresting  topics. But, I think that the most important thing I learnt this week is that the past could give us answers for the future.

I'm really enjoyed this course!!!

PLIOCENE vs TODAY

On May 9, 2013, carbon dioxide levels in the atmosphere reached the level of 400 parts per million (ppm). The last time the Earth experienced this level of carbon dioxide was in the Pliocene about three to five million years ago. Investigate what the temperatures were during this time period and compare them to today. What could explain the changes?


The last time atmospheric CO2 was at 400ppm, humans didn't exist. It was during the ancient Pliocene era, tree million years ago. If we compare the temperatures in that periode with the tempertatures today, we can observe great diferences:

• In the Piocene the global average temperatures were 3 to 4 ºC warmer than today and the polar temperatures were 10ºC warmer too.
• In the Pliocene the Artic was ice free and the sea level was between 5 and 40 meters higher.

However, the most important diference is that in the Pliocene a higher concentration of CO2 would have been entirely down to natural earth processes. Nowadays, the increase of CO2 levels has been happening much more rapidly today than it did during que Pliocene epoch because of the industrialization, the human activities, burning fosil fuels and other process have changed the amount of greenhouse gases emitted into the atmosphere. Therefore we will progressively continue see climate changes over the next years.



Sources:

http://www.esrl.noaa.gov/gmd/ccgg/trends/weekly.html
https://en.wikipedia.org/wiki/Pliocene
https://scripps.ucsd.edu/programs/keelingcurve/2013/12/03/what-does-400-ppm-look-like/
http://www.skepticalscience.com/pliocene-snapshot.html

RECENT PAST CLIMATE CHANGE

What are climate change records?

To understand the world's climate and how it was changed, there are many measurements that scientist have to evaluate.

An obstacle in evaluating past climate change is the fact that a lot of observations are not complete. Climate observations were mainly limited to weather situations and ships, and included measurements made near the land or ocean surface. 

In recent years things have improved, ballon soundings have been widespread over the land, satellites have covered all world and there has been an increase in sub-surface monitoring.

But there are no records of measurements bafore 1600s so scientifics have to use other types of information to investigate further back. These kind of data are called indirect or proxy measurements.

They use the tree-rings to determinate the chages in temperature and precipitation. A tree grows and it adds a new ring around its waistline each year so climate conditions have influence in the tree-ring widths.

The ice-cores have accumulated from snowfall over many millennia so, ice cores can tell to scientifics about temperature, precipitation, volcanic activity and wind patterns.

Coral reefs can be used to obtain measurements about temperature and sea-level changes. Corals build their hard skeletons form calcium carbonate. The calcium carbonate contains isotopes of oxygen that can be used to determine the temperature of the water in wich the coras grews.

Finally, scientist can use the polen grains to identify the type of plant from which they came and identify at what time the sediment, where the pollen laid, was deposited.

Sources:  http://www.ncdc.noaa.gov/news/what-are-proxy-data

How volcanos have influence in climate change?

During this week we have seen that the gases and dust particles thrown into the atmosphere during volcanic eruptions have influences on climate.

Volcanic ash or dust released into the atmosphere during an eruption shade sunlight and cause temporary cooling. Larger particles let sunlight in but do not let heat radiation from the Earth’s surface out, and the result is a warmer Earth. Small ash particles form a dark cloud in the troposphere that block some of the incoming energy from the Sun and the Earth cools. Most of these particles fall out of the atmosphere within rain a few hours or days after an eruption. But the smallest particles of dust get into the stratosphere and are able to travel vast distances, often worldwide. These tiny particles are so light that they can stay in the stratosphere for months, blocking sunlight and causing cooling over large areas of the Earth.

Another component has influence in the climate change. Often, erupting volcanoes emit sulfur dioxide into the atmosphere. The sulfur dioxide moves into the stratosphere and combines with water to form sulfuric acid aerosols. The sulfuric acid makes a haze of tiny droplets in the stratosphere that reflects incoming solar radiation, causing cooling of the Earth’s surface. The aerosols can stay in the stratosphere for up to three years, moved around by winds and causing significant cooling worldwide. Eventually, the droplets grow large enough to fall to Earth.

Sources:
http://earthobservatory.nasa.gov/Features/Aerosols/

http://volcano.oregonstate.edu/how-do-volcanoes-affect-atmosphere-and-climate
http://scied.ucar.edu/shortcontent/how-volcanoes-influence-climate


How is today’s warming different from the past?

The Earth’s climate changed due to natural causes in the past. Most often, global climate has changed because of variations in sunlight, the effect of volcanic eruptions, variations in the Earth's orbit and fluctuations in the energy that the sun emits. 

These natural causes have influence today but too small compared to human activity. For example, although volcanoes continue to emit carbon dioxide, the amount of carbon dioxide is extremely small compared to human emission because the world population is a little over a trillion today which implies that carbon dioxide emissions have considerably increased.

Sources: http://earthobservatory.nasa.gov/Features/GlobalWarming/page3.php


What is the role of isotopes in determining temperatures from the past?

The carbonate is the key to know about past temperatures. Originally, carbote is dissolved in the oceans and it forms the shell of a little sea animal, the foraminifera. Studying the shell of this animal through the carbonate that forms it, scientifics can discover how temperatures have changed.

Carbonate contains oxygen, whose atoms exist in two naturally-occurring stable isotopes, ¹⁸O and ¹⁶O.The ratio of these two isotopes in the shells tells us about past temperatures.

The variability of ¹⁸O in the ocean determinates the temperature. This way, when water evaporates in warm climates, the molecules of ¹⁶O tends to evaporate first, so it has more ¹⁸O in places where lots of water evaporates and less where it rains a lot.
¹⁸O isotope is the first to back down into the oceans in form of precipitation, therefore shells have high levels of this isotope.

Changes in climate that alter the global patterns of evaporation or precipitation can therefore cause changes to the background δ¹⁸O ratio.  

Sources: http://www.giss.nasa.gov/research/briefs/schmidt_01/


How have trees been used to reconstruct different climate variables across the world?

Dendrochronology or tree-ring dating is the method of scientific dating based on the analysis of tree ring growth patterns. Tree rings vary in width denpendent on fast or slow growth patterns during warm or cold periods. the density of cells reflects on the growth patterns (low density results in thin rings, high density produces thick rings). Tree could also have diseases or additional enrichment, which result in the varying growth patterns also.

Tree-rings can provide continuous yearly paleoclimatic records for regions or periods of time with no instrumental climate data. However, different species respond to different climate parameters. Scientifics have to consider when dating trees that most trees are not old enough, so the records do not date back as far as other sources of climate data. This is when crossdating is important to identify similar growth patterns across many trees and make a longer timeline of climate data.This way, increasing the amount of trees utilised to study, the best crossdating results can be obtained.

Sources:
http://web.utk.edu/~grissino/principles.htm#1
http://www.windows2universe.org/earth/climate/CDcourses_treerings.html
https://www.ncdc.noaa.gov/news/picture-climate-how-can-we-learn-tree-rings

How can ice cores provide a record of atmospheric composition?

The most important property of ice cores is that they are a direct archive of past atmospheric gasses. Air is trapped at the base of the firn layer, and when the compacted snow turns to ice, the air is trapped in bubbles.The air bubbles are extracted by melting, crushing or grating the ice in a vacuum.This method provides detailed records of carbon dioxide, methane and nitrous oxide going back over 650,000 years

Also, it is possible to discern past air temperatures from ice cores. This can be related directly to concentrations of carbon dioxide, methane and other greenhouse gasses preserved in the ice. The ratio of oxygen isotopes in the snow reveals temperature, though in this case, the ratio tells how cold the air was at the time the snow fell. In snow, colder temperatures result in higher concentrations of light oxygen.

Sources:
http://www.antarcticglaciers.org/glaciers-and-climate/ice-cores/ice-core-basics/
http://www.earthobservatory.nasa.gov/Features/Paleoclimatology_IceCores/

PAST CLIMATE CHANGE

When we think about climate change it's easy to wonder what happened in the past. This week we are going to learn more about how our climate has changed over the last 4.5 billion years.

The Earth's climate has changed many times before. There have been times when most of the planet was covered in ice, and there have also been much warmer periods. Over at least the last years, temperatures and carbon dioxide levels in the atmosphere have increased and decreased in a cyclical pattern.

To understand this cyclical pattern the BBC has published a series of documentaries on snowball Earth. Link or Youtube

Snowball Earth describes the coldest climate inmaginable. In the distant past the Earth froze over from pole to pole. 

But, how could it be possible?

We know that our climate is controlled by some feedbacks and cycles, particulary in this case, the ice albedo feedback, the water cycle and the carbon dioxide cycle. 

 

ICE ALBEDO FEEDBACK

These cycles can be summarised in this diagram which explain the process of the snowball Earth theory:

 

Amazingly, the Earth is capable of selfregulating, with a series of mechanisms that work together and surprisingly gases like carbon dioxide played a powerful role in governing global climate.

Further information in these links;
Snowball Earth
http://www.bbc.co.uk/nature/ancient_earth/Snowball_Earth
https://www.youtube.com/watch?v=Dv0e-zGGgjQ 
http://globalwarmingsimplified.weebly.com/ 

MINDMAP

It'sreally important to think about how organize your ideas because a good organisation can make easier to undertand a topic.


I have found some interesting pages that allow me to elaborate a MIND MAP online.

You can export your mind map as .pdf file .png file, print it or save it.


mindmapfree.com/

https://www.mindmup.com/


You are probably wondering what a mind map is so, a mind map is a diagram used to visually organize information. A mind map is often created around a single concept, written in the center of a blank landscape page, to which associated representations of ideas such as images, words and parts of words are added. Major ideas are connected directly to the central concept, and other ideas branch out from those.

 


For me It's a extraordinary way to organize my ideas about the topic I have been studing.

I created this two mind maps about the topics studied this first week of the course. I hope they will be useful for you.